XenoPort Announces Initiation by NIAAA of Clinical Trial of HORIZANT in Patients with Alcohol Use Disorder

SANTA CLARA, Calif.--()--XenoPort, Inc. (Nasdaq:XNPT) and the National Institute on Alcohol Abuse and Alcoholism (NIAAA) announced today that the NIAAA has initiated a clinical trial of HORIZANT® (gabapentin enacarbil) Extended-Release Tablets as a potential treatment for alcohol use disorder (AUD).

“This multi-site, well-controlled clinical trial will allow us to evaluate the safety and effectiveness of gabapentin enacarbil in treating AUD,” said George F. Koob, Ph.D., director of the NIAAA. “Gabapentin has shown promising results in earlier clinical trials, and the development of new medications is an important component of our commitment to broaden the range of treatment options for people with AUD.”

The NIAAA plans to enroll approximately 350 subjects in a randomized, double-blind, placebo-controlled clinical trial of HORIZANT in patients with AUD at approximately 10 sites in the United States. The study will assess the efficacy of 1200 mg of HORIZANT (administered in two daily doses of 600 mg each) compared with placebo to reduce drinking in subjects who report four or more symptoms of AUD, as defined in the Diagnostic and Statistical Manual of Mental Disorders – Fifth Edition (DSM-5). Eligible subjects will receive either HORIZANT or placebo for 26 weeks, to include one-week escalation, 24-week maintenance and one-week taper periods. The primary objective of the study is to compare the efficacy of HORIZANT with matched placebo on the primary alcohol consumption outcome, which is percentage of subjects with no heavy drinking days during the last four weeks of the treatment.

Ronald W. Barrett, Ph.D., XenoPort’s chief executive officer, stated, “We are happy to be working with the NIAAA on this important clinical trial. We believe that the differentiated pharmacokinetic features of HORIZANT make it particularly well-suited for testing in this patient population. Our prior joint discussions with the U.S. Food and Drug Administration have indicated that positive results from this study, along with other supporting data, could enable us to move forward rapidly to file a supplemental New Drug Application for HORIZANT as a potential treatment for AUD. We believe patients with AUD are seriously underserved by current FDA-approved treatments.”

About Alcohol Use Disorder (AUD)

AUDs are medical conditions that doctors diagnose when a patient’s drinking causes distress or harm. The fourth edition of the Diagnostic and Statistical Manual (DSM–IV), published by the American Psychiatric Association, described two distinct disorders—alcohol abuse and alcohol dependence—with specific criteria for each. The fifth edition, DSM–5, integrates the two DSM–IV disorders, alcohol abuse and alcohol dependence, into a single disorder called alcohol use disorder, or AUD, with mild, moderate, and severe subclassifications.

According to the 2013 National Survey on Drug Use and Health, 16.6 million adults ages 18 and older, or approximately 7.0 percent of this age group, had an AUD in 2013. About 1.3 million adults received treatment for an AUD at a specialized facility in 2013, representing less than 10 percent of adults who needed treatment for AUD.

About HORIZANT

Discovered and developed by XenoPort, HORIZANT (gabapentin enacarbil) is a prodrug of gabapentin. In the United States, XenoPort has six issued patents listed in the FDA’s Orange Book for HORIZANT that have expiration dates between 2022 and 2029.

For further information about the NIAAA clinical trial of HORIZANT in patients with AUD, please go to www.ClinicalTrials.gov or click the link below:

https://www.clinicaltrials.gov/ct2/show/NCT02252536?term=NIAAA+and+gabapentin+enacarbil&rank=1

Background of Gabapentin in AUD Clinical Studies

Data from previously completed clinical trials indicate that oral gabapentin may reduce alcohol craving and alcohol withdrawal symptoms. In addition, single-site clinical trials have also shown that in alcohol dependent patients who are abstinent at treatment initiation, gabapentin delayed the onset to heavy drinking and improved the symptoms of insomnia. In these studies, gabapentin was generally well-tolerated.

About XenoPort

XenoPort, Inc. is a biopharmaceutical company focused on developing and commercializing a portfolio of internally discovered product candidates for the potential treatment of neurological disorders. XenoPort is currently commercializing HORIZANT® (gabapentin enacarbil) Extended-Release Tablets in the United States and developing its novel fumaric acid ester product candidate, XP23829, as a potential treatment for patients with moderate-to-severe chronic plaque-type psoriasis and potentially for relapsing forms of multiple sclerosis. REGNITE® (gabapentin enacarbil) Extended-Release Tablets is being marketed in Japan by Astellas Pharma Inc. XenoPort has entered into a collaboration with the NIAAA for the potential development of HORIZANT as a treatment for AUD and has granted exclusive world-wide rights for the development and commercialization of its clinical-stage oral product candidate, arbaclofen placarbil, to Indivior PLC for all indications. XenoPort's pipeline of product candidates also includes a potential treatment for patients with idiopathic Parkinson's disease.

To learn more about XenoPort, please visit the website at www.XenoPort.com.

Forward-Looking Statements

This press release contains “forward-looking” statements, including, without limitation, all statements related to the potential clinical development of HORIZANT; the suitability of gabapentin enacarbil as a potential treatment of AUD; future regulatory discussions and the timing thereof; the possibility of utilizing the proposed study as the basis for an sNDA filing for HORIZANT for patients with AUD; the expected study design and enrollment in the clinical trial of gabapentin enacarbil, and the timing thereof; and the therapeutic and commercial potential of gabapentin enacarbil. Any statements contained in this press release that are not statements of historical fact may be deemed to be forward-looking statements. Words such as “believe,” “could,” “expected,” “goal,” “hopeful,” “may,” “planning,” “possibility,” “potential,” “proposed,” “will” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon XenoPort's current expectations. Forward-looking statements involve risks and uncertainties. XenoPort's actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, the difficulty and uncertainty of pharmaceutical product development and the uncertain results and timing of clinical trials and other studies, including the risk that success in preclinical testing and early clinical trials do not ensure that later clinical trials will be successful, and that the results of clinical trials by other parties may not be indicative of the results in trials that XenoPort or its partners may conduct; XenoPort’s and the NIAAA’s ability to successfully advance gabapentin enacarbil development and to conduct clinical trials in the anticipated timeframes, or at all; the risk that the completion of clinical trials for gabapentin enacarbil may be delayed or terminated as a result of many factors, including delays in patient enrollment; that gabapentin enacarbil may require significant additional clinical testing prior to any possible additional regulatory approvals; the uncertainty of the FDA’s review process and other regulatory requirements; the uncertainty of protecting and expanding XenoPort’s intellectual property rights, including the risk that patent rights may not provide XenoPort with sufficient protection against competitive products or otherwise cover commercially valuable products or processes; XenoPort’s dependence on collaborative partners; and the uncertain therapeutic and commercial value of XenoPort’s product candidates. These and other risk factors are discussed under the heading “Risk Factors” in XenoPort’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2015 filed with the Securities and Exchange Commission on May 7, 2015. XenoPort expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in the company's expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.

HORIZANT, REGNITE and XENOPORT are registered trademarks of XenoPort, Inc.

Source code: XNPT2C

Contacts

XenoPort, Inc.
Jackie Cossmon, 408-616-7220
ir@XenoPort.com

Contacts

XenoPort, Inc.
Jackie Cossmon, 408-616-7220
ir@XenoPort.com